Nosepiece stiffener for faired towlines



April 28, 1970 H. v. CORDIANO ETAL 3,508,515

NOSEPIECE STIF'FENER FOR FAIRED TOWLINES Filed Nov. 27, 1968 2 Sheets-Sheet l 667/761? L/IVE INVENTORS H060 V. imam/v0 BY JOHN G. M3330 Z aim.

A ril 28, 1970 H. v. CORDIANO ETAL 3,508,515

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IIIIIIIIIII IIIIIIIIL Filed Nov. 27, 1968 United States Patent 3,508,515 NOSEPIECE STIFFENER FOR FAIRED TOWLINES Hugo V. Cordiano, Brooklyn, and John G. Maeco, Massapequa Park, N.Y., assignors to the United States of America as represented by the Secretary of the Navy Filed Nov. 27, 1968, Ser. No. 779,327 Int. Cl. B63b 21/00 U.S. Cl. 114-235 Claims ABSTRACT OF THE DISCLOSURE Bending of a sectionally faired towline at the towingvessel towstaff is reduced by a nosepiece stiffener consisting of a rigid plate which replaces the nosepieces of a plurality of sections of fairing at the end of the towline which connects with the towstaif on the towed body. In addition to the stiffener plate, additional stiffening is provided by replacing the plastic aligner rods by stainless steel aligner rods and the chain links between bolts by plate links.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to faired towlines and especially to a means for reducing the bending of such towlines at the towpoint.

In towing a body or vehicle, at a depth behind a towing vessel, it has been found that vehicles have been lost by breakage of the towline at the towpoint (the point at which the towline is connected to a receiving device, such as a towstaff, on the towed body). This point is subjected to severe bending stresses because of undesired lateral movements (yaw) of the towed body.

An object of this invention is to reduce the stress produced by the yawing of a towed body on the end of a faired towline at the point at which the towline connects to the towstatf of the towed body.

A further object is to facilitate the launching and retrieval of a towed body by a towing vessel.

The objects and advantages of the present invention are accomplished by replacing the nosepieces of several sections of a faired towline at the towstalf end by a single, rigid-plate nosepiece, thereby reducing the bending force exerted on the flexible portion of the towline by a moment developed on the towstaif during a yaw of the towed body.

Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a diagrammatic representation of a towstatf and a towline without a nosepiece stiffener;

FIG. 2 is a diagrammatic representation of a towstaff and a towline with a nosepiece stiffener;

FIG. 3 is a diagrammatic illustration of a portion of a conventional, sectionally faired towline attached to a towstaff;

FIG. 4 is a diagrammatic illustration of an embodiment of the invention;

FIG. 5 is an end view of the nosepiece stiffener plate as seen from the edge labeled A in FIG. 4.

FIGS. 1 and 2 show the principle underlying the invention. A towstaff is mounted in a swivel mounting 12 which is affixed to the towed body (not shown). (The view which is shown is a top view of the apparatus the one which would be seen by an observer at the ocean surface who is looking into the water at the towed vehicle and the towline 14.) The mounting 12 is capable of 3,508,515 Patented Apr. 28, 1970 ice vertical movement but is not capable of lateral movement; therefore, any yawing movements of the towed body result in the situation shown in the figures. A yawing movement produces a moment M around the vertical axis through point 11 on the towstaff. The moment M results in a bending force at the towpoint 16, the force being F =M/9 if it is assumed that the distance from the point 11 to the towpoint 16 is 9 inches.

The result of stiffening a length of the towline 14 at the towstaff end is shown in FIG. 2. It can be seen that if a length of towline 14 is stiffened so that it is rigid and is rigidly affixed to the towstaif 10, the effect is to effectively lengthen the towstatf 10 and reduce the bending force at the new bending point 20, the bending force now being F =M/ 33 if the distance from the point 11 to the new towpoint 20 is now 33 inches. The reduction takes place because the bending force is inversely proportional to the distance from the point 11 to the bending point.

FIG. 3 shows a diagrammatic illustration of a conventional towstatf 10 and sectionally faired towline 14 (five sections are shown). The towstaif 10 here consists of a fin 22 and a roughly semicircular slab 24 of metal from which the fin 22 extends. The towline cable 26 enters a hole 28 bored through the semicircular part of the towstatf 10. A small section of the cable 26 the part directly adjacent to the fin 22 is uncovered; the rest is enclosed by the fairing 30, specifically by the nosepiece 32 of each fairing section. Each fairing section also has a fairing fin, or tailpiece, 34. Plastic aligner rods 36 are enclosed within the tailpieces 34, extending between adjacent tailpieces and between the towstaff fin 22 and the tailpiece 36 closest to it. Bolts 38 hold the assemblage together and are linked by chain links 40 when they lie close to the edge of a fairing section.

FIG. 4 illustrates how a nosepiece stiffener 18 which may be fabricated from stainless steel, for example, is utilized to replace four nosepieces 32, each of which is six inches long. The stiffener 18 is also wider than the nosepieces thereby providing more effective stiffening of the four fairing sections, so that the aligner rods 36 on the intermediate fairing sections are unnecessary.

Additional stiffening is provided by replacing with a stainless steel rod 42 the plastic rod 36 which extends between the towstaif fin 22 and the first fairing tailpiece. Also, the chain links 40 are replaced by plate links 44.

In FIG. 5, the cross-section of the nosepiece stiffener 18 is seen to be substantially U-shaped. This permits the enclosure of the towline cable 26 in the curved section and permits the tailpiece sections of the fairing to be inserted between and bolted to the straight sides of the stiffener 18.

It has been found in tests of the present invention that the nosepiece stiffener reduces the bending force, thereby minimizing towline breakage and also appreciably reduoes fish-tailing of the towerd body during launch and retrieve operations, thereby greatly facilitating the accomplishment of these operations.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

We claim:

1. In a sectionally faired towline for an underwater towed vehicle having an attached towstaff to which the towline is coupled, each fairing section having a nosepiece enclosing a section of the towline cable and being bolted to its associated tailpiece section, the improvement comprising:

towline stiffening means having a length equal to that of several nosepieces, said means being used in place 4 of said several nosepieces, with one end of said said plate links being used to link the adjacent pairs stiffening means being located adjacent to said towof bolts in said towstaff and its adjacent tailpiece staff, section, and to link the adjacent pairs of bolts in said stiffening means acting to extend the effective length each adequate tailpiece section enclosed by said of said towstalf, thereby reducing the bending force 5 stiffening means. on said towline at the top point thereof, 5. Towline stiffening means as in claim 3, wherein 2. Towline stiffening means as in claim 1, wherein said towstaff has a section which is formed in the shape said stiffening means comprises rigid plate material having of a fin, said stiffening means being attached to said a U-shaped cross-section in the curved section of which fin section of said towstaff. said cable is carried. 10

3. Towline stiffening means as in claim 2, said means References Cited having at least one aligner rod fabricated from a rigid material such as stainless steel and extending between UNITED STATES PATENTS the towstaff and the adjacent fairing-section tailpiece. 3,092,067 6/1963 Arm t 4. Towline stiffening means as in claim 3, said means 15 3,352,274 11/1967 c lkin having plate links and bolts,

said bolts being used to fasten said stiffening means to TRYGVE M. BLIX, Primary Examiner said towstafi and to said several tailpiece sections, 

